In a small bowl, whisk the gelatin with 1/3 cup of the buttermilk. Let stand for 5 minutes.

In a small saucepan, combine the milk and honey and warm over low heat, stirring, just until the honey dissolves. Remove from the heat and whisk in the gelatin mixture until dissolved. Whisk in the lime juice and remaining 2/3 cup of buttermilk. Pour the pudding into six 6-ounce cups or ramekins. Cover and chill overnight until set and firm. Garnish with the raspberries and lime zest.